The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In a TMED type hybrid vehicle equipped with a DCT, a motor operated by electricity is mounted on a DCT and an engine clutch is disposed between the motor and an engine, in which the power from the motor can be supplied to odd-numbered shafts for shifting to odd-numbered gears and even-numbered shafts for shifting to even-numbered gears through two clutches of the DCT, and the clutch for supplying power to the odd-numbered shafts is called an odd-numbered clutch and the clutch for supplying power to the even-numbered shafts is called an even-numbered clutch.
In the DCT described above, gears are sequentially disposed between the odd-numbered shafts and the even-numbered shafts, so shifting is sequentially made to the gears on different shafts by engaging/disengaging the odd-numbered clutch and the even-numbered clutch, and this type of shifting is called different-shaft shifting because two shafts are used for shifting.
Since such sequential shifting is biaxial shifting, it is possible to make smooth shifting without torque reduction of driving wheels due to clutch-to-clutch switching by disengaging the clutch for the current engaged gear and engaging the clutch for a new desired gear to be engaged, after the new desired gear on the shaft disengaged from the corresponding clutch. Accordingly, if possible, the DCT makes this sequential shifting, and for skip shifting that skips the next gear when a vehicle speed is rapidly changed or a vehicle is rapidly accelerated by a driver, it may be required to shift to another gear on the same shaft.
This type of shifting on the same shaft is called same-shaft shifting, and of this type of shifting, in order to make power-off down-same-shaft shifting that shifts to a lower gear having a larger gear ratio without an accelerator pedal pressed down by a driver, it is required to disengage the current engaged gear with the corresponding clutch disengaged, to engage a new desired gear, and then to engage the clutch. However, the corresponding clutch is engaged after slip synchronization for removing a speed difference because the speed of the input shaft mounted with the desired gear is higher than the speed of a driving source of the vehicle such as an engine or a motor, so shifting takes long time in this case.